Physics P1 - Red Shift

What is red shift and what does it tell us?

Red shift is when the frequencies from galaxies are lower than they should be, they have moved to the red end of the electromagnetic spectrum.

Red shift is proof that the universe is expanding and galaxies are moving further away from us.

The more distance galaxies have greater red shifts than closer ones. This tells us that the distant galaxies are moving away from us more quickly.

If you are struggling to understand red shift, imagine a racing car, the pitch of the noise is lower as it moves further away from you. This is called the doppler effect. Then imagine that the frequncies get lower as it moves further away!